Not very traumatic for me but it was for the bird. I was doing about 80 on my K1100LT on a straight Nevada backroad. Saw a robin come in fast-n-low from the right but didn't see him exit to the left. Didn't think much of it at the time.
When I got to my camping spot for the evening I looked down to find a feather and some blood on my boot:
(http://home.comcast.net/~smithduck/tours/bmw8/bmw8_album/slides/b8_1476.jpg)
There was more evidence on the bike and I'd guess that the crash bar took him out:
(http://home.comcast.net/~smithduck/tours/bmw8/bmw8_album/slides/b8_1472.jpg)